The invention relates generally to control apparatus for supplying air to the cleaning chamber of a combine. More specifically, the invention is directed to control apparatus for regulating a fan baffle plate to control the amount of air being used in the cleaning and separating phases of the combine operation. The air supply is automatically controlled in response to the intake manifold pressure.
A combine generally includes a harvesting means for removing a quantity of a crop material from a field. The harvesting means is operatively connected to a feeder means or conveyor which moves the crop material to a separator. The separator receives the crop from the feeder and removes the grain from the total harvested crop material. The separator is connected to a cleaning chamber. The cleaning means removes trash materials from the grain by supplying a predetermined volume or supply of air to the grain and trash material delivered by the separator. The cleaning means often includes a fan or blower which supplies the air to the grain. In current state-of-the-art combines, the amount of air being taken in by the fan to the cleaning means of the combine is constant. An operator of the combine manually sets the position of a fan choke such as a baffle plate at the beginning of the harvesting process. The volume of air taken into the fan means is sufficient to clean and separate the grain from the crop material when the combine is operating at full capacity. However, in many situations the combine is not operating at full capacity. For example, when the combine is being turned in the fields, or when the combine is being unloaded, the volume of air being taken into the combine by the fan means is often too great. During these situations, the intake of crop material into the combine is greatly reduced. As such, the volume of air is too great for the amount of grain being harvested. This often results in the grain being expelled from the combine along with the chaff and trash material. This often results in a waste of grain. In many prior art combines, the fan choke means is manually operated. The fan choke means is operatively connected to an indicator and crank means located in the operator's station. The indicator and crank means must be manually operated in order to adjust the fan choke means. Many times, this must be done while the combine operator is concentrating on the various other functions of the combine machine. Often, the combine operator is preoccupied with the intricacies of maneuvering the combine machine and does not act to close the fan choke means. As such, the volume of air being supplied from the fan means to the cleaning and separating means is too great for the quantity of grain material being harvested and cleaned. The large volume of air acts to blow the cleaned grain out of the combine along with the trash materials.
Thus, there is a need for a control apparatus such as a fan choke means that automatically and consistently regulates the air being taken into the combine machine. There is a further need for control apparatus that can be adapted to accommodate a variety of combines having fan choke means with various internal components and dimensions.